DETROIT, MI - Metro Detroit home values have been rising by double-digits for more than a year, and though on-market inventory finally edged up last month, it still remains low.

That means with all the rising values and selling prices, the market is still not considered completely healthy by Realtors' standards.

The latest report on home values says in Metro Detroit they rose 15 percent year-over-year in April, according to S&P/Case-Shiller Home Price Indices data released Tuesday.

The hard-rebounding Detroit-area’s annual rise was dwarfed only by the metros of Las Vegas 18.8 percent, San Francisco 18.2 percent and San Diego at 15.3 percent on the 20-city composite. Together, the 20 cities tracked by S&P/Case-Shiller on the index rose 10.8 percent.

And prices are still not at the same rate that were before the market meltdown.

According to the S&P/Case-Shiller report, Detroit's price index stood at 95.3 in April, making it the lowest-valued housing market on the 20-city composite.

“In Metro Detroit the home values actually had gone up to 120-125, then went down to 70 in 2008 and 2009," said Mike Kruczek, Chief Lending Officer at DFCU Financial. "So that’s telling you the dollar value that homes have lost."

Now, almost near its baseline of 100, the market is getting healthier. And sales may be down, but they are picking up, especially in some of the suburbs, Kruczek said. “In the very desirable communities like Ann Arbor, Bloomfield Hills and Birmingham, homes are being listed and sold on the same day,” he said.

But in much of the metro area, many homeowners still find themselves "underwater" on their mortgages, meaning that their properties would sell for less than what they owe banks on the homes.

That, in large part, is what has kept inventory levels low, according to Kruczek. “Prior to recession, Southeast Michigan would have been 60,000 homes for sale,” he said. “Now there’s about 18,000. Things have changed dramatically.”

According to Realcomp, in tracking Southeast Michigan and parts of northern Ohio, inventory in the region actually edged up for the first time in five years on an annual basis in May.

On-market inventory edged up to 22,037 homes on the market last month, compared with 21,928 in May 2013. On the year, short sale listings fell by 70 percent, and foreclosure listings dropped 26 percent.

David Muller is the business reporter for MLive Media Group in Detroit. Email him at dmuller@mlive.com or follow him on Twitter